One
of the most significant measures of this winter is the "persistence" of
cold temperatures, with only brief respites of above normal
temperatures. Since December 1st, 2013 nearly 70 percent of all days
have brought colder than normal temperatures to Minnesota. There are
several other "indicators" of how cold this winter has been:

A
preliminary climate summary shows that Minnesota recorded the 4th
coldest December-January combination in history (back to 1895) with a
statewide average temperature of 3.8 degrees F, about 8 degrees F colder
than normal. The only colder combinations of December-January were in
1917-1918 (1.4 F), 1976-1977 (1.7 F), and 1978-1979 (2.7 F). Neighbor
Wisconsin also recorded its 4th coldest December-January combination
with a statewide average temperature of 8.5 degrees F, also about 8
degrees F colder than normal. The only colder combinations of
December-January temperatures in Wisconsin were 1976-1977 (5.2 F),
1917-1918 (6.6 F), and 1919-1920 (7.4 F).

Despite consistent snow
cover, frost depth in the soil has progressed downward, even more so
where snow cover is thin. Some reported frost depths from around the
state:

Since
December 1, 2013 Minnesota has reported the coldest temperature in the
nation 35 times, including twice already in February. This is a higher
frequency than any other state, including Alaska which reported its
mildest December-January combination since the winter of 2000-2001.

As
of Friday, February 7th the Twin Cities reports 40 days with a low
temperature of 0 degrees F or colder. This is the largest number of
such temperatures since the winter of 1981-1982. So, a whole generation
of Twin Cities residents have never experienced persistent cold of this
kind. The last time the number of days with minimum temperature of 0
degrees F or colder exceeded 50 during winter in the Twin Cities was
1977-1978 when 53 such readings were reported. You can read more about
this from Pete Boulay in the State Climatology Office at...http://www.dnr.state.mn.us/climate/journal/at_or_below_zero_13_14.html

The
Duluth Office of the National Weather Service reports that as of
February 7th, Duluth has recorded 19 consecutive days with minimum
temperature readings below 0 degrees F. If this pattern persists until
Monday, February 10th, the historical record for consecutive days with
low temperatures below 0 degrees F will be tied, 22 days, which occurred
in 1936 and 1963. The forecast for Duluth suggests that overnight lows
will remain below 0 degrees F into early next week. You can read more
at...http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=dlh&storyid=100188&source=0

MPR's
chief meteorologist Paul Huttner will help from Dr. Jay Austin of the
Large Lakes Observatory in Duluth wrote about the extent of ice cover on
Lake Superior in a recent Updraft blog. It appears the lake is nearly
completely ice covered and has the most ice in 18 years. With continued
cold temperatures Lake Superior may become as ice-covered as it was in
1979. There is a great deal of fast ice anchored to the shoreline that
extends out through shallow waters. You can read more at...http://blogs.mprnews.org/updraft/2014/02/polar-vortex-winter-lake-superior-freezes-over-a-month-early/

Our
energy bills are also impacted by the cold weather. Many communities
in the state are reporting the highest number of Heating Degree Days
(aggregate sum of mean daily temperatures below 65 F) for the period
November 1 to January 31 since the winters of 1995-1996 and 1996-1997.
This statistic is likely reflected in your large heating bill.

Greg
Spoden, Minnesota's State Climatologist notes that even by the
standards of Embarrass, MN it has been a cold winter. Observer Roland
Fowler of Embarrass reports 23 nights with temperatures of -30 degrees F
or colder this winter, compared with an average of just 9.

MPR listener question

"There have been reports this winter about the deep and abiding cold
perhaps increasing the mortality of forest insects like the Emerald Ash
Borer (-30 degrees F or colder) and the pine bark beetle (-40 degrees F
or colder), but what about agricultural pests? Do you think some of
them will be set back by this cold winter?"

Answer: Most
agricultural insects that overwinter in Minnesota are well adapted to
climate conditions here according to University of Minnesota
entomologists. Secondly, many of these species overwinter in the soil
or in the vegetation of hedgerows and field boundaries. These
environments are protected by snow cover as insulation, so the risk of
exposure to lethal temperature conditions is reduced. However, there
may be some higher mortality inflicted on certain agricultural pests
this winter. For example soybean aphid eggs, often laid on common
buckthorn or other vegetation may be exposed to the lethal temperatures
we have had so far this winter. Temperatures colder than -29 degrees F
are lethal to soybean aphid eggs, and certainly many places in Minnesota
have seen temperatures that cold this winter.

Twin Cities Almanac for February 7th

The
average MSP high temperature for this date is 23 degrees F (plus or
minus 13 degrees F standard deviation), while the average low is 5
degrees F (plus or minus 14 degrees F standard deviation).

MSP local records for February 7th

MSP
weather records for this date include: highest daily maximum
temperature of 53 degrees F in 1987; lowest daily maximum temperature of
-14 degrees F in 1933; lowest daily minimum temperature is -29 degrees F
in 1875; highest daily minimum temperature of 36 F in 1925; record
precipitation of 0.94 inches in 1928; and a record 4.1 inches of snow
fell on this date in 2001. Maximum snow depth on this date was 22
inches in 1967.

Average dew point for February 7th is 5 degrees F,
with a maximum of 38 degrees F in 1965 and a minimum of -32 degrees F
in 1972.

All-time state records for February 7th

The
state record high temperature for this date is 62 degrees F at Browns
Valley (Traverse County) and Madison (Lac Qui Parle County) in 1987. The
state record low temperature for this date is -53 degrees F at Leech
Lake Dam (Cass County) in 1899. State record precipitation for this date
is 1.75 inches at Lynd (Lyon County) in 1928; and state record snowfall
for this date is 14.0 inches at Campbell (Wilkin County) in 1946.

Past weather features

A
snow storm dropped 9 inches of snow at Ft Snelling on February 7, 1857
and 14 inches at Princeton, MN. The winter of 1856-1857 was one of the
coldest and snowiest of the 19th Century in Minnesota.

On a
statewide basis the coldest February 7th in history occurred in 1933.
Twenty Minnesota communities saw the thermometer drop to -40 degrees F
or colder, and a few places fell to -50 degrees F. The high temperature
at St Peter that day was -14 degrees F, same as the Twin Cities. The
below 0 F weather lasted until February 10 when the temperatures finally
climbed into the teens and twenties F.

The warmest February 7th
in state history occurred in 1987 when over 70 Minnesota communities saw
the mercury climb to 50 degrees F or greater. Dozens of observers
reported reach 60 degrees F as well. It was 50 degrees F as far north
as Walker and Itasca State Park, with little snow on the ground.

Outlook

Partly
cloudy skies and cold over the weekend, with a chance for snow in the
south on Saturday. Continued cold until Wednesday when temperatures
will start to moderate closer to normal and there will be an increased
chance for snow.

Further information

NOTE: News releases were current as of the date of issue. If you have
a question on older releases, use the news release search (upper
left-hand column of the News main page) or the main Extension search (upper right of this page) to locate more recent information.